docs: def constrain_opts(self, constraint_dict, options):
          """ Return result of constraints and options against a template """
          constraints = {}
          for constraint in constraint_dict:
              if constraint != 'self':
                  if (constraint_dict[constraint] or
                          constraint_dict[constraint] == ''):
                      constraints[constraint] = constraint_dict[constraint]
          results = self.constrained_sections(constraints=constraints,
                                              options=options)
          return results, self.template